+ macOS Services: The rules in this group basically allow all connections to the domain apple.com for all processes. This includes usage statistics collected by Apple, location services, crash reports and so on. Enable this rule group if you trust Apple and if you don’t want to decide these things one-by-one.

+ iCloud Services: The rules in this group allow all connections to iCloud for all processes. Enable this rule group if you want to use iCloud services built into macOS and third-party apps.After the first installation, Little Snitch show a Welcome Window asking you which of these rule groups you want to enable. You can re-play this Welcome Window by choosing Help > Welcome to Little Snitch in Little Snitch Configuration.

You can enable or disable rule groups at any time. Open Little Snitch Configuration and have a look at the Rule Groups section in the left sidebar.